In real life, Joy had two sons: Douglas Gresham (who was depicted in this movie) and David Gresham (who was not). David was born in 1944, and Douglas in 1945. After their mother's death, David and Douglas continued to live with their stepfather, C. S. Lewis. In contrast to his mother, stepfather, and younger brother, David was less interested in converting to Christianity, and while still a child living with Lewis, he started to return to Judaism. According to Edwin Brown's book "In Pursuit of C. S. Lewis", Lewis was very supportive of David's interest in Judaism, including finding a kosher butcher to supply his meat.
In one of the scenes, in which Douglas Gresham (Joseph Mazzello) is reading in bed, he is reading The Hobbit by J.R.R. Tolkien. Tolkien was a good friend and colleague of C.S. Lewis.
Sir Anthony Hopkins prefers to memorize lines on his own, while Debra Winger prefers extensive on-set rehearsals. To accommodate Winger, producer and director Sir Richard Attenborough rehearsed with her, reading Hopkins' lines.
The title is from The Chronicles of Narnia: The Last Battle, by C. S. Lewis, from the chapter "Farewell to Shadowlands".
Douglas Gresham (along with his brother, David) became the heir to C.S. Lewis' literary estates, and is one of the producers of The Chronicles of Narnia film franchise.